myty - Don't get me wrong - I wasn't trying to be a S.A. - besides, I just learned you can edit what you post. I have made my share of errors and misspellings (thank goodness for Spell Check !), and thanks, Ed -

Yep - the plants were on "rock & roll" back then. We were pouring 2500 tons per day at Tonawanda MCP.

That certainly was a lot of metal moving - Can you relate just how the metallurgy changed and/or was tracked during much of the casting in a sense of the quality control of the molten batches when so much is being poured and so quickly?I've heard where '010' and other notations cast behind the timing chain and bellhousing areas referred to the metallurgy content of pour batches in that more Nickel and maybe Tin were introduced into the composition when pouring certain batches of blocks. Is this in fact true and if so why and how were any additional alloy amounts introduced and/or monitored? Also, what if true is the reason to pour such blocks verses any others ie: was there a reason for such blending to be done or needed?Having worked in and around smelters and assay labs in the nickel industry here in Canada for years, I find such things interesting and my own 302 has some of these casting notations on the block and I always wondered if it was really true that it designed for 'performance blocks' needing maybe more strength over 'regular' ones..Thanks - Randy

It would take a lot of typing to fully answer the metallurgical control question. Suffice it to say that the primary alloying & adjusting elements were Carbon, Silicon, Manganese, and chrome. "Base" iron was melted and the alloy composition was adjusted in the hot metal cranes as they were filled from the holding furnaces (in front of the cupolas). Further adjustments were made at the individual molding lines. There were only two basic types of iron. Blocks & drums required a higher chrome for wear and/or tensile (class 30 iron). Carbon, silicon, and chrome were further adjusted at the mold lines (as the metal was poured into the pouring ladles) for additional strength, and casting feeding requirements. Gray iron producers were cupola melters back then, so Manganese was used to "tie up" excess sulfur in the iron. Foundry metallurgy was essentially controlled/analyzed by eutectometers (carbon & silicon analysis via cooling curve) and chill samlpes (carbide tendency). The full lab with spectrometer, Leco, wet lab, and mechanical testing was located at the forge (next door to the foundry) - connected via pneumatic transport tube. Believe me - that's the "cliffs notes" version!

I've heard where '010' and other notations cast behind the timing chain and bellhousing areas referred to the metallurgy content of pour batches in that more Nickel and maybe Tin were introduced into the composition when pouring certain batches of blocks.

That's a common misconception - the "010/020" cast into that front bulkhead identifies the common core pattern used for two different blocks, not any metalllurgy.

The Z blocks weren't cast at Tonawanda.. but instead all HP, and SHP small block engines were cast and built at Flint., I think.... waiting on JohnZ to respond re the 'high nickel' question on 302 blocks..

#2 mold line at Tonawanda cast small blocks - they could have (and were at times) shipped to Flint for solid lifter application. All cylinder iron (both plants) was the same spec. We did some really unusual alloying for some siamese bore race blocks. Special alloying just wasn't done in production though - too hard to keep track of with 2,500 tons of iron being poured per day.

OK. Thanks Bergy.. but it sure makes one wonder where the initial information came from (re high nickel content) that has been reported in the auto mags *forever* re the Z28 blocks....? How does such information get started and propagated for so long in supposedly 'knowledgable magazines'??

It just proves we drank the koolaid. I waited from month to month waiting for the next update on the HotRod Camaro SS in '67. I think Vic Edelbrock owns it now? 50 years later I found out it was ALL a lie. HotRod lied about all the stats, even the "396" was really a blueprined 427.

John, Was the metallurgy 'high nickel'? or not? I've read that in the car mags since the cars were new .....?

Gary

Nope. I don't know where that "010/020" high-nickel thing started, but it took on a life of its own, like many other misconceptions; I believed it too for a while, until I researched it and a friend of mine who has worked at the Saginaw Foundry (now called Saginaw Metal Casting Operations) for 37 years debunked the story and explained what the numbers mean. Those numbers just identify the core pattern for the front bulkhead.